Educational Low-Cost Frequency Response Analyzer using Arduino and Software Octave

Frequency response method is an important approach in the design and analysis of plants and controllers. Bode plot is a simple technique to graphically represent a system frequency response. Getting the Bode plot from experimental data would help students to be motivated and understand the frequency response method, which is usually taught through simulations or theoretical examples. There are tools that allow getting the experimental Bode plot of a plant, but they are expensive. This paper presents an educational low-cost system that experimentally gets the Bode plot using Arduino. The sound card of the notebook intended for programming the Arduino is used to generate the sinusoidal voltages used to get the plant frequency response. A phase detector and two peak detectors allows getting the phase delay and the gain for different frequencies. Those data are sent to the notebook, where a processing program developed in the open-source Octave software used those data to create the Bode plot. Experimental results shows that the proposed hardware can be easily applied as an educational tool to understand frequency response through Bode plot.